A magnetic memory device comprises a magnetic memory chip including a plurality of magnetoresistive elements and a magnetic layer (magnetic shield layer) having a closed loop structure in which in a cross section of the magnetic memory chip, the magnetic layer continuously surrounds the magnetic memory chip.
The magnetic layer having the closed loop structure shields the magnetic memory chip from an external magnetic field or adjusts a magnetization reversal characteristic (hysteresis characteristic) of each of the magnetoresistive elements. For example, in the case where a magnet is provided in the magnetic layer having the closed loop structure, magnetic lines of force from the magnet make a loop passing through the magnetic layer having the closed loop structure. Thus, the nonuniform of a magnetic field applied to the magnetoresistive elements can be reduced. Therefore, the shift of the magnetization reversal characteristics of the magnetoresistive elements can be canceled by the magnetic fields, thus improving the function of the magnetic memory device.